USE OF P63 IN ASSESSING MIMICS OF PROSTATIC ADENOCARCINOMADR. A. T. ATANDA, BAYERO UNIVERSITY/AMINU KANO TEACHING HOSP.KANO

BACKGROUND

Prostatic carcinoma has several well documented mimics, particularly on core needle biopsy, for which the pathologist cannot rely on morphology alone for their differential diagnosis.

Correct evaluation of these mimics will help prevent unnecessary treatment for cancer.

Mimics of Prostatic Carcinoma

AtrophyBasal Cell HyperplasiaAdenosisSeminal vesiclesGangliaParaganglia

AIM

To evaluate the reliability of morphology alone measured against immunohistochemistry in evaluating equivocal prostatic biopsies.

METHODOLOGY

p63 immunohistochemical stain (clone BC4A4)

equivocal impressions of benign versus malignant diagnoses over a

12-month period (Jan – Dec., 2013)

Negative stain = positive for malignancy

Positive stain = negative for malignancy

Criteria for diagnosis of CaP

Major criteria infiltrative acini which may have

cribriform dispositionabsence of basal cells; and nuclear and/or nucleolar

enlargement. Minor criteria included: adjacent high grade PIN and nuclear hyperchromasia

others mucinous fibroplasia, perineural

invasion and glomerulations

Results61 cases of CaP27(44.3%) were considered

equivocal. 6 (22.2%) of the 27 showed

basal cell staining 3 cases of atrophy basal cell hyperplasia clear cell cribriform

hyperplasiaUrothelium

Results

The probability of erroneous interpretation ranged btw 8.7% and 42.3%

PPV of morphology alone was 77.8%.

RESULT ctdSensitivity of 100% (83.8% to 100%);

Specificity of 77.8% (57.7% to 91.3%);

NPV of 100%.

Discussion Our study 22.2% reclassified; Error rate

8.7% (sensitivity:77.8%; specificity: 100%)

7.5% error rate reported by Berney et at1 (London)

1.3% documented by Epstein et al2 in the US

100% and 64%.3

Reasons for lower specificity by morphologySurgeons

Sample adequacy (volume & number)

Crush artifacts Cauterization artifacts

Pathologists Good sections inexperience

Discussion

The use of immunohistochemical staining for p63

protein alone, or as a component of a cocktail

comprising p63, alpha-methyl-CoA-racemase

(AMACR) and Cytokeratin CK903,3 is also gaining

momentum.

conclusionFor improvement in diagnosis of carcinoma of prostate, particularly from core needle biopsies, there is need for pathologists to pay attention to the common mimics of carcinoma and incorporate immunohistochemistry into their diagnostic armamentarium.

1. Berney DM, Fisher G, Kattan MW, Oliver RT, Møller H, Fearn P, et al; Trans-Atlantic

prostate group. Pitfalls in the diagnosis of prostatic cancer: retrospective review of 1791 cases

with clinical outcome. Histopathology 2007; 51: 452-7.

2. Epstein JI, Walsh PC, Sanfilippo F. Clinical and cost impact of second-opinion pathology:

review of prostate biopsies prior to radical prostatectomy. Am J Surg Pathol 1996; 20: 851-7.

3. Tokumaru Y, Harden S V, Sun D I, Yamashita K, Epstein J I, Sidransky D. Optimal use of a

panel of methylation markers with GSTP1 hypermethylation in the diagnosis of prostate

adenocarcinoma. Clin Cancer Res 2004; 10: 5518-22.

References

z